Intermittent catheterization is a good option for many users who suffer from various abnormalities of the urinary system. A common situation is where single use, individually packaged, sterile catheters are used. An important criterion for any single use product is the cost of the product, i.e., a less expensive product is desired and valued.
It is also quite common for catheters to be provided with a surface treatment using a lubricant to reduce friction in order to allow for easier and less traumatic insertion. Currently, there are two major categories of catheters having lubricated surfaces, i.e., gel coated catheters and hydrophilic coated catheters.
The gel coated catheters are made easier to insert by application to the catheter surface of a water-based gel that can be applied by the user, or more conveniently, it can be supplied with the packaged catheter. Typically, a system is provided with the packaged catheter to apply the gel to the catheter surface. This system may be one where the gel is put onto the catheter surface just before or during the packaging operation or one where the gel is applied to the surface as the catheter is being inserted by the user.
In a hydrophilic coated catheter, the catheter is provided with a thin hydrophilic coating which is adhered to the outer surface of the catheter. When this coating is activated by swelling in contact with a hydrating liquid such as water, it becomes an extremely low coefficient of friction surface. The most common form of this product is where a sterile, individually packaged single use catheter is provided in a dry state or condition. The user opens the package, pours water into the package, waits 30 seconds, and then removes the catheter from the package, now ready for insertion.
A more recently introduced version of the hydrophilic coated catheter is where the catheter is provided in a package that already contains enough loose liquid water to cause it to be immersed. For this product, the user simply opens the package and removes the catheter ready for insertion without the need to add water and wait 30 seconds. Other new products provide the amount of liquid water necessary for immersion of the catheter in a separate compartment of the package. With these products, one must open the separate compartment of the package allowing the liquid immersion water to enter the catheter-containing chamber for direct contact with the hydrophilic coated surface. Depending on the product, and on the amount of water in the separate chamber, the user may be asked to manipulate the package to bathe the catheter surface in the hydrating liquid in order to activate the hydrophilic coating on the catheter surface. The catheter is then removed from the package ready for insertion by the user.
In all of these existing products, the catheter depends upon direct contact of the liquid swelling medium (e.g., liquid water) with the entirety of the hydrophilic coated catheter surface. Moreover, all of these existing products achieve this direct liquid water contact by providing a package for the catheter that permits liquid water to flow freely within the cavity of the package, and permits unobstructed access to the catheter surface. Because of the free flow of loose liquid water within the package and unobstructed access to the catheter surface, it is easy to ensure direct contact of the liquid swelling medium with the entire surface of the catheter that has been treated with the hydrophilic coating.
A disadvantage of the hydrophilic coated catheters described above is that the immersion liquid has a tendency to spill from the package as the user handles the catheter and tries to remove it for subsequent insertion. Another disadvantage of the hydrophilic coated catheters described above is that the catheter has an extremely slippery surface which makes it quite difficult for the user to handle during insertion.
For catheters that are removed from the package and then inserted, there is another disadvantage in that the handling of the catheter by the user will introduce microorganisms onto the surface of the catheter which can cause infectious problems after being introduced into the body during catheter insertion. To address this issue, manufacturers have devised systems whereby the catheter can be inserted by the user without first removing the catheter from the package, thus requiring the user to touch only the package, and not the catheter surface. These systems tend to work well for gel coated catheters, and they have the additional advantage that the user does not get gel on his or her hands as the catheter is being inserted. Another version of the gel lubricated catheter utilizes a sleeve around the catheter which is attached to a gel reservoir at the insertion end of the catheter whereby the gel reservoir and sleeve come out of the package attached to the catheter which is inserted by advancing it through the gel reservoir. In this type of product, the sleeve fits the catheter diameter very loosely, thereby allowing the catheter and the integral funnel which is typically provided on the distal end of the catheter to slip past the sleeve surface as the catheter is advanced by the user during insertion.
For hydrophilic coated catheters, there has also been consideration of delivery of the catheter without first removing it from the package, but a serious problem for this type of approach is the tendency of the immersion liquid to spill. Hydrophilic coated catheters with sleeves of any kind have generally not been available, because the presence of the sleeve interferes with the flow of liquid water to the catheter surface that is required for activation by direct liquid contact. Some designs are described in the patent literature where the hydrating liquid is inside of a hose member that can be used as a no touch delivery vehicle (See, for example, United States Publication No. 2003/0018322 A1, published Jan. 23, 2003). These described hose members are stiff, though, and require special concertina folds to allow for advancement of the catheter, and special gripping sections to allow for gripping of the catheter.
In some of the published patent art, for example, U.S. Pat. No. 6,059,107, there is discussion of keeping low the amount of water placed in the package with the catheter. They propose to do this, however, by simultaneously providing a narrow cavity around the catheter tube thereby using the design of the cavity to accomplish a reduction in the amount of water. In this way, the catheter remains substantially immersed in and subject to direct liquid water contact while contained in the package.
In one commercial product, the cavity is not completely filled with water, and so recommendation is made to the user to tilt or otherwise manipulate the package prior to use, to ensure direct liquid water contact with the catheter in order to fully activate the hydrophilic surface coating. Similarly, some commercial products with a liquid reservoir that is to be ruptured prior to use do not have enough liquid water to fill the package cavity that holds the catheter. The user is instructed to tilt the package multiple times to cause liquid water to move over the catheter to activate the hydrophilic surface coating by direct liquid water contact. As mentioned above, the liquid water in the package cavity presents a spill hazard for the user when the package is opened to use the catheter. As will be appreciated, the spill hazard is greater for hydrophilic catheters that more completely fill the package cavity with liquid water, whereas more patient manipulation is required for hydrophilic catheters that fill the cavity less completely with liquid water.
There is a tradeoff then, between undesirable alternatives with existing hydrophilic catheter products. On the one hand, the package cavity is provided with a quantity of liquid water designed to keep the catheter substantially immersed, but there is a significant spill hazard. On the other hand, when there is less liquid water relative to the overall package cavity volume, the user must manipulate the package prior to use to ensure activation of the catheter coating. The present invention avoids this tradeoff by eliminating any spill hazard while requiring no user manipulation.